Living in and Enjoying a Sound Mind
Unlike Cain, a Christian has a new spirit (2 Corinthians 5:17) and can therefore determine what happens in his mind. He can rule over his mind by consistently feeding his spirit with the Word, that way his spirit has dominance over his mind. He can determine his thoughts (Philippians 4:8), and he can control how he reacts to his feelings (1 Corinthians 9:27).